Bit



July 24, 1928 N. BOWMAN BIT Filed Ag. 21, 1926 Patented July 24, 19.28.

Umran "s'rAri-:s PATENT, OFFICE.

Application led August 21, 1926. Serial llo. 180,686.

This invention relates to coal mining machinery and has special reference tothe bits and bit mounting means. The, invention has for its object the provision of a bit especially' adapted for cutting through rock, and also has for its object the pro' vision of bit-holding meanswhich will firmly hold the bit while in use and may be very easily and quickly manipulated to permit release of va worn out bit or the insertion of anew bit. The invention. is illustrated in the accompanying drawing and consists in certain novel features which will be particularly pointed out in the claims appended to the following description.'

. In the drawing:

Figure 1 is a sectional elevation of a chain lug having my .improved bitmounted therein in accordance with the present invention;

' 20 Fi 2 is a view. similar to Fig. 1 showing the bit in elevation and the holder and wedge .in section;

Fig. 3 is a gig. 4 is a al1 ,f .f Fig. 5 is a rear elevation ofthe wedge. The lug, indicated as an entiret by the reference numeral I, is of the usua general formation, having eyes 2 at its inner corners to receive plvot bolts lwhereby it will be connected to and between chain links. In the outer portion of the body of the lug is a chamber or recess 3 receiving the bit, the bit holder and the wedge.

The bit 4 is rhomboidal inside view and in cross section is of a flat diamond shape having its acute angles rounded olf, as indi- .cated at 5 and 6, thereby forming cutting points 7 at the diametricall opposed sharper angles of the rhomboid. actual practice, the bit is so disposed that one cutting point 7 will be projected forwardly and outwardly and thereby properly positioned to penetrate the material upon which the machine is to act, and it will be obvious that, when one point is worn down so as to be no longer useful, the bit maybe reversed andthe op- ,posite' sharp point utilized as the cutting instrumentality. The time spent in sharpening bits of the ordinary construction 1s thus saved and a very substantial reduction in the cost of operation and maintenance is front elevation of the bit;

front elevation .of the holder,

eaed. The particular form of the bit shown and described also facilitates eco- 'nomical production. In `manufacturing the blts I provide a long blank which is rolled to the flattened diamond cross section shown v in Fi 3, and this long strip or blank is run t rough a cutting machine which, at

regular intervals, cuts through 'and acrossl the blank in oblique relationv to the side edges thereof so that the blank will be rapidly sub-divided into short sections, each sectlon constituting a finished bit. Obviously, the cost of manufacture by this process is` so slight as to be negligible.

The holder 8 is a solid block having its greater dimension equal to or sli htly greater than the depth of the recess or c amber 3 so that the block may fit closely between the top and bottom Walls of the said chamber and against the rear wall thereof, a small lug or teat 9 being formed uponl the rear side of the holder at the inner end` thereof to engage a corresponda seat inthe rear jwall of the chamber 3, as w1 be underalong the side portions of the holder and across the end'thereof to provide an inwardl diverging seat orv so'cket which fits over t e outer ortion of the bit at the rear end thereof.

tendency of the bit to rotate or move laterally and the holder is provided at its inner end on its front face with a forwardly projecting shoulder 13 cooperating with the socket elementl2 to maintain the bit in its y his socket-forming rib 12 fits closely about the bit so that it resists any stood upon referenceto Figs.` 1 and 2. The front face 10 of the holderv 8 is disposed operative position. Within the chamber A3,'

in advance of the bit and the holder 8, is disposed a wedge 14, the inner end of which is. adapted to fit uarely lagainst Athe inner wall of the ,said c extremity, o n its rear side, the fwedge is provided `with an overhan 'ng shoulder 15 adapted to rest against t e shoulder .13 of 10ol amber and near its inner the holder, the holder and the wedge having a right gular formation at these engaging. or lateral points so' that relative twistin movement between the wedgean theholder I will be prevented. The rear portion of the wedge is cut away, as indicated at 16, from the shoulder 15 to the the' we formed a outer extremity of and a groove or recess 17 is ong this cut-away portion, the forward wall 18 of which is disposed' obliquely 1,5 tion ofthe bit will that there is an open space at `the sides of 30 the device which extends from the outer ends i releasing movement of the wedge.

l0 wall of the 1ug 1 in such wedge, the front face thereof is of the h/lder and the'wedge to the points of engagement of theshoulders' 13 and 15 so that the clearance will be 'suicient to permit theinsertion or removalof a bit upon slight The rfront face of the wedge is provided between its inner and outer ends with an elongatednotch receiving the inner end of a set bolt 21 mounted'in a threadedbore in the front osition that it is ada ted to bear .against t e bottom of the saidp notch betweenthe ends of the same. -Between the notch and the inne' end of the as cline'd,'as indicated at 22, to facilitate the insertion of the parts in the lug after the .holder andfthe bit have been assembled with the wedge.

" this forma/tion the assembled holder, bit and wedge` may be inserted endwise 1nto the chamber 3 until the holder and -wedge impnge against the inner wall of the chamber, ani then a rear movement imparted thereto toengage the lug-9 within the seat provided ltisalso to be noted that the end Walls of thefnotch'20prevent accidental release and loss 'of' the wede'and bit in the event that the Setbolt 21 s it is set. Obviously,

f wed e against the bit and the bit against the vhol er,. the .holder being, in turn, clamped thereby aa'mst the rear wall of the chamber 88o t'at the parts the shoulder 13`foln'1s a stop andabutment .which effectively prevents the bit under the im 4eration ofthe machine.. pens that, in .actual operation, the set bolt 21 1s loosened 'a halfturn orpossibly a ,'fu1l turn but jsueh loosening of the bolt :isnot sullclent to permit removal of rthebit and vthe blt cannot be remeved unless the of the bmkenA rock and dust before slightly inf- It will be understood that by l ould not remain as tight as' the' set bolt is turned,-

home against the wedge so as to clamp the Jug', a wedge seating in the/lug in'advance of v der and 'provided on its front' facet i with spaced shoulders, a retaining bolt mounted inthe lug and engaging the wedge are very tlghtly se jb cured wlth the front face of the holderand between the holder and thel ing ilthe rear face of the wedge. s

3. The combination with' a maof`l a holder seating. 1n the yielding. osedethereon` in the opj It sometimes hap- `flug-and havin an obliquely dlsposed'portion'and having a transverse shoulder at the inner end of said obhquel'y disposed portion, (a socket' formed wedge around 'theontler -endp portion of'such obis withdrawn. The shoulders at the ends of the notch 20 prevent withdrawal of the wedge unless the 'sct bolt be loosened suliiciently to clear said shoulders'or end wa'lls prevailing' practice it is exceedingly apt to be broken linto s uch small' particles as to be merely dust and be undesirable commercially. No efricient bit has been provided heretofore for cutting through the strata of rock above or below the vein of coal, but

my improved bit is especially adapted forl the rock below the vein of coal so that the coal vmay besubsequentlybroken down in ygood commercial condition. By tunnelling .and is intended to permit the tunnelling of through the rock before breaking 'down the I i coal vein, the operators may clean away all down the coal s that, when the coal is broken down, it will be clean and of good marketable quality. Inasmpch as this method' eliminates the necessity of screening or cleaning the coal the cost of mine operationis very materially reduced.'

Having thus described claim:

1. The combination of a mining machine chain lug, a holder seating inthe lug and havinga forwardly and outwardly inclined straight front face,

rear face Gdisfposed obliquely relative to the front face o and held' by the same, the opposed faces of the holder and the wedge conforming to the bit so as to closely engage the same -and the entire area ofthe rear end face of the bit wedge to prevent withdrawal from the lug.

2. The combination with a'minin' machine chain lug, of a holder seating 1 nthe the ho l etween said shoulders,- anA front face ofthe holder and the chine chain lug,

g'its front face formed with breaking a wedge 'seatlng in the ug in advance of the holderand having its 'the holder, a rhomboidal bitdisposed between the holder and the wedge a 'bitdisposed' dwedge' and seat' the invention, 1

110 abutting the front face of the holder, and f means mounted in the. lug and engaging the mav liquely disposed part of the holder, a wedge seating in and having obliquely disposed the lug in advance the inner portion of its rear face of the holder with respect to the holder 5 and` constructedl with a longitudinally extending seat lel with the holder, a bit disposed between the holder and the wedge and fitting in the socket on the holder and the seat mounted in the lug and engaging the wedge to revent Withdrawal.

n testlmony whereof I affix m signature.

NEWTON K. B WMAN.

on the wedge, and means 10 

